Russia has carried out new and extensive attacks on Ukraine's power grid.
In disputed front-line areas, several Ukrainian civilians have been killed by Russian projectiles and shelling.
"Another difficult night for the Ukrainian energy sector", announced the Ukrainian energy giant DTEK on Thursday morning.
One of its thermal power plants had been hit in a Russian attack and suffered "serious damage". The company does not disclose which plant or where. Three people are reported to have been injured in what DTEK says is the seventh major attack on its facilities in just a few months.
"The enemy attacked several energy facilities", reports Ukraine's energy ministry.
Half capacity
In Kiev, air raid sirens sounded on the streets early in the morning as drones targeted the city, but according to the Ukrainian military, all were shot down. Several of Ukraine's regions were attacked in different ways, and in the Vinnytsia region, it is reported that hundreds of thousands of households were left without electricity.
Out of a large number of projectiles, a total of four rockets got past Ukraine's air defence, according to military sources.
The recent targeted attacks on Ukraine's power grid have halved its capacity compared to a year ago, according to President Volodymyr Zelensky. Planned power outages are taking place, and it is likely that there will be more in the coming weeks.
Ukraine's army chief has described the recent escalation as an attempt by Russia to advance as far as possible before Ukraine receives new weapons deliveries.
Russia's military describes the recent attacks as targeted strikes against Ukraine's military power supply, in response to Ukrainian drone attacks on oil facilities in Russia.
Several civilians killed
In Donetsk in the east, several civilians have been killed in the past 24 hours. In one attack, three people were killed by Russian cluster ammunition, and in another, one was killed by a glide bomb, according to the Ukrainian governor Vadym Filashkin.
In Kherson, north of the annexed Crimea peninsula, two civilians are reported to have been killed by Russian shelling. In the Kharkiv region in the northeast, where Russia is trying to make a ground offensive, a civilian woman was killed by Russian fire.
In Krasnodar in Russia, attacks were also reported on Thursday morning. According to the authorities, one woman was killed.